Power equipment are widely used for the transformation of voltages and currents with high power values in substations (SEs), such as, for example, transformers. One difficulty currently found relates to the integration of digital systems with existing technologies for supervision of the electrical system in a logical basis which facilitates efficiency and agility of the operation. One such example are transformers with tap equivalence, often of different models, manufacturers and powers, among other features in a substation. In addition, there are often difficulties in obtaining conclusive information about the regulatory and parallelism system deployed in a pre-existing substation. There is also difficulty in finding economically viable solutions that meet strict criteria and are of high reliability and efficiency as set forth by the National Electrical System Operator (ONS).
Systems prior to the present invention did not have satisfactory digital control technologies, because existing solutions do not solve the problem of the substations having integration among voltage sources and/or energized gaps using dedicated electrical equipment with wires for voltage regulation and parallelism thereof. In addition, previous systems: (a) do not meet the strict criteria of reliability, safety and performance; (b) do not meet all the requirements established by ONS network procedures; (c) do not meet the necessary operational features, including automatic changes of voltage reference values; (d) are not applicable for any quantities and types of high voltage sources and/or energized gaps, such as transformers, and for any amounts of voltage levels; (e) are not equipment and/or manufacturer independent; (f) are not inexpensive.
Treetech® offers products applied to voltage regulation line such as physical devices provided with readings and commands as a function of load curves. These devices do not interact with other devices of different manufacturers and models in a satisfactory manner, in particular, in large quantity and also do not efficiently integrate with existing alarms and supervision.
The present invention, on the contrary, provides a solution for automation projects for the regulation and parallelism among different models of voltage sources and/or high voltage energized gaps which: (a) does meet the strict criteria of reliability, safety and performance; (b) does meet all the requirements established by ONS network procedures; (c) does meet the necessary operational features, including automatic changes of voltage reference values; (d) is applicable for any quantities and types of high voltage sources and/or energized gaps, such as transformers and/or autotransformer banks, and for any amounts of voltage levels; (e) is equipment and/or manufacturer independent; (f) is inexpensive.
The invention solves the problem of integration to obtain conclusive information about the regulation and parallelism system deployed in a pre-existing substation among the different devices and interfaces. For example, preferred embodiments of the invention are applicable in 230/69 kilovolt (kV) and 230/138 kV power substations, for which positive results have already been demonstrated, also being applicable to other types of substations/high voltage sources.
In the patent literature, some partially relevant documents were located, which will be described as follows.
Document U.S. Pat. No. 5,498,954 shows a method for controlling at least two high voltage regulators, each regulator having a tap switch, comprising operation in parallel, determining output voltage and reactive power of each regulator and determining the tap position for each regulator. The present invention differs from said document, apart from other technical reasons, in that it provides a computer implementable method and has master-slave architecture. In addition, the method of said document has functional requirements not present in the present invention: it makes MVAR flow measurement at the bottom of a transformer, requires average voltage measurements at the bottom through a programmable logic controller (PLC); it requires the PLC to calculate a voltage as a function of reactive power for each transformer with the goal of avoiding certain differences among transformers.
Document U.S. Pat. No. 5,210,443 shows a process for parallel control in selected switched combinations of tap switches of a plurality of transformers in parallel comprising the detection of the transformer tap settings, output voltage and current measurement and processing, and regulation of such transformers as a function of such variables. The present invention differs from said document, apart from other technical reasons, in that it provides a computer implementable method and has master-slave architecture, which were not cited in said document. In addition, the method of said document has functional requirements not present in the present invention: there is a need for measurement of current amplitude values and current phase angles; the need for calculation of partial load current and circulating reactive current for transmission to the voltage regulators; the need for calculation of variables in individual voltage regulators in order to determine new setpoints for individual voltage regulators.
From what can be understood from the searched literature, we found no documents anticipating or suggesting the teachings of the present invention, so that the solution proposed herein, to the eyes of the inventors, has novelty and inventive step in view of the prior art.